PROJECT SUMMARY/ABSTRACT The 1990 Americans with Disabilities Act (ADA), 1999 Olmstead Supreme Court Decision, and ADA Amendments Act of 2008 are supposed to protect people with serious mental illness (SMI) against discrimination by considering institutionalization as the last resort to be used only if integrated community-based services are not a viable alternative. Despite these federal mandates, nursing homes may have replaced state psychiatric hospitals as the default source of care. Nursing homes now serve more adults with mental illnesses than all other healthcare facilities combined. Between 10-25% of nursing home residents are thought to have SMI. Residents with SMI are often younger than the typical resident and require services that nursing homes might not be able to provide. Knowledge is lacking about the current extent of this potential warehousing of working-age adults with SMI. We propose using data from the 2011-2016 federally mandated, longitudinal Minimum Data Set 3.0 and Certification and Survey Provider Enhanced Reporting files to conduct an observational longitudinal observational study of adults between the ages of 22 and 64 years with SMI residing in nursing homes. Our specific aims are to: 1) estimate the overall prevalence of SMI among these working-age nursing home residents and to describe the length of stay by psychiatric disorder; 2) examine receipt of psychiatric treatment for these residents; and 3) use latent variable models to identify distinct subgroups of functioning among those with SMI and describe relationships between these subgroups, resident and facility characteristics, and disposition status. This proposal addresses the National Institute of Mental Health?s Strategic Objectives 2: to chart mental illness trajectories to determine when, where, and how to intervene and 4.1: to improve the efficiency and effectiveness of existing mental health services through research. This exploratory research will inform efforts to improve the delivery of mental health services to a particularly vulnerable population by illuminating the current care needs of working-age adults with mental illness.